The invention relates to a door for closing a front-side loading opening in the housing of a washing machine or tumble dryer, wherein two door shells are connected by means of a hinge to the housing in such a way that the door can be pivoted through an opening angle of at least approximately 180° and in the closed position is countersunk in a front wall recess in such a way that it terminates flush or approximately flush with the front surface of the housing.
In a commercially available appliance of this kind, the door is fitted with a transparent cup-shaped window which is inserted between a retaining ring forming the inside of the door frame and a front-side panel frame and is mechanically firmly locked in position by the connection of the two frame parts. The stability of the door is substantially dependent on the frame which is made of plastic. The door is endowed with a necessary flexural and torsional rigidity due to the shape of the frame parts and due to reinforcing ribs and ridges recessed on the inside. The doors of the type that is of interest here are moved by hand. For this purpose they have a handle or a handle area which usually lies opposite a hinge or is disposed offset slightly upward opposite the horizontal center line.
The load acting on the hinge is determined on the one hand by the door's own weight and on the other hand by the force applied by the user when opening and closing the door. The hinge of a washing machine or tumble dryer is expected also to have sufficient stability in the event that the user leans slightly on the open door.
Customer wishes for the best possible view into the interior of the appliance and the most convenient access possible to the drum during the loading and unloading operation can only be met by a large door overall and a large transparent window mounted in the door frame. The mechanical loads acting on the hinge and its fixing to the door frame increase in proportion to the size of the door.
For reasons of design, in particular in the case of an appliance that is intended to be installed in a row of furniture units, it is advantageous if the door terminates flush with the front surface when in the closed position. The flush arrangement of the door can also be necessary for practical reasons. A door which because of its size extends close to the side edges of the appliance should not, or should only slightly, stick out from the plane of the appliance front in order to avoid abutting edges.
A front-flush door also affords advantages in the packaging of the appliance. Given housing dimensions that are otherwise the same, said packaging can be kept somewhat smaller and all precautionary measures to protect the projecting door separately can be dispensed with.
A hinge device for a door to be arranged flush into the front plane is known from DE 198 04 962 C1, for example. The solution described there is characterized by a particularly large swiveling angle of the door. Essential features of said hinge are a hinge strut and a control strut which are mounted with adjacent axes behind the front wall and project outward with a curved section through an opening in the front wall and are hinged with their outer ends to a door flange by means of two outer axes. When the door is opened, it is swiveled firstly about the inner axis and in the same direction of rotation about an outer axis. By means of such a hinge the door fitted flush in the front wall can be brought out from the plane of the front.
However, the manufacture of a hinge of this kind consisting of many individual parts is complicated and comparatively expensive. The two swivel axes make the hinge heavy and unstable and its fixing to the door requires a very stable frame due to the great weight. In particular with large and consequently heavier doors a significant amount of effort and expense is necessary in order to achieve the robustness necessary for such a hinge.